1. Field of the Invention
The present invention relates to a small light-source module to which a small single-point light source such as an LED is mounted as a light source, and to a light-source unit constituted by an arrangement of a plurality of such modules.
2. Related Art
Light-source units using LEDs (light-emitting diode) have come to be used in vehicles as brake lamps. In this application, because the light-emitting angular range of an LED is limited when it is packaged, it is necessary to use a large number of LEDs to approach the condition of a light-emitting surface.
Accordingly, it is an object of the present invention, in consideration of the above-noted condition, to provide a small light-source module capable of emitting light that is close to a surface light source with as large a surface as possible, using one small single-point light source such as an LED having a limited light-emitting angular range, and to provide a light-source unit that, by using such a small light-source module, is capable of providing surface light emission with a large surface area, while using only a small number of light sources.
To achieve the above-noted objects, a first aspect of the present invention is a small light-source module having a small single-point light source emitting light over a prescribed light-emitting angular range and a reflective surface, the small single-point light source having a light axis that is tilted with respect to the reflective surface, and the outer contour of the reflective surface being substantially fan-shaped, so as to correspond to a projected light region produced on the reflective surface by the small single-point light source, the fan-shaped reflective surface being provided on the body of a substantially fan-shaped module, the small single-point light source being mounted to the module body, and the reflective surface having thereon a reflective pattern that reflects the light emitted from the small single-point light source as parallel light.
By causing the light from the small single-point light source to strike the reflective surface at an inclination thereto, the light is reflected over a large fan-shaped surface. Therefore, when using a small single-point light source such as an LED having a limited light-emitting angular range as a light source, it is possible to produce a condition that is close to surface light emission over as large the maximum surface area possible, thereby enabling a reduction of the number of light sources with respect to the light-emitting surface area. Furthermore, because it is possible to impart a certain directivity while broadening the light-emitting surface, this arrangement is suitable for use in brake lamps for vehicles, for example.
A second aspect of the present invention is a variation on the first aspect, wherein the small single-point light source is provided on an inside surface of the module body, and wherein the reflective surface is integrally provided in an inner surface of the module body, the reflective pattern being provided as a surface pattern on the inner surface of the module body.
In this aspect of the present invention, because the reflective surface is provided on the inner surface of the module body, this arrangement is suitable for the case in which the module body is made of a transparent material. Furthermore, because the reflective pattern is provided as a surface pattern integral to the inner surface of the module body, the task of making the pattern separately and then affixing thereto.
A third aspect of the present invention is a variation on the first aspect, wherein the small single-point light source is provided on an inner surface of the module body, the reflective surface is provided on an outer surface of the module body, which is made of a transparent material, and the reflective pattern is integrally formed in an outer surface of the module body.
The module of the third aspect is made when the module body is made of a transparent material, in which case because the reflective pattern is integrally formed in the outer surface of the module body, it is possible to provide a lens or the like on the inner surface. Additionally, by providing the reflective pattern on the outer surface, processing is facilitated.
A fourth aspect of the present invention is a variation on the third aspect, wherein an array of small lenses is provided on the inner surface of the module body.
Because the module has an array of small lenses on the inner surface of the module body, light that reaches the reflective surface and light after reflection can be collected or dispersed by the lenses, thereby enabling the production of a condition that is closer to surface light emission.
A fifth aspect of the present invention is a variation on any one of the first to the fourth aspects, wherein reflective surface comprises a concave curved surface with respect to the small single-point light source, and wherein a reflective pattern is formed that is constituted by a multiple-step parabolic surface for making the reflected light parallel light.
In this module, because the reflective surface is a concave surface, it is possible to capture all the light from the light source, and possible to increase the reflection efficiency. By using a reflective pattern that is a mutliple-step parabolic surface, it is possible to achieve uniform directivity in the reflected light, even with a compact module body.
A sixth aspect of the present invention is a light-source unit having a plurality of light-source modules having disposed therein a small single-point light source according to any one of the first to the fifth aspects arranged in a radial pattern within a plane, so that the narrowed ends of the module bodies thereof face toward the inside of the unit and the opposite broadened ends of the module bodies thereof face toward the outside of the unit, this arrangement being integrally mounted in a round housing.
In this light-source unit, by using small light-source modules having outer shapes that are substantially fan-shaped, and arranging the modules in a radial pattern within a round housing, it is possible to achieve compactness and produce a round surface light emission with a high light intensity.
A seventh aspect of the present invention is a light-source unit having a plurality of light-source modules having disposed therein a small single-point light source according to any one of the first to the fifth aspects arranged in a radial pattern within a plan, so that the narrowed ends of the module bodies thereof face toward the outside of the unit and the opposite broadened ends of the module bodies thereof face toward the inside of the unit, this arrangement being integrally mounted in a round housing.
In this light-source unit, by arranging the substantially fan-shaped modules in a circle with the opposite orientation from the sixth aspect, it is possible to achieve a distinctive design, which when used as a signaling light is highly visible, thereby improving safety.
An eight aspect of the present invention is a light-source unit having a plurality of light-source modules having disposed therein a small single-point light source according to any one of the first to the fifth aspects arranged vertically in a linear pattern, wherein the narrowed ends of the module bodies thereof face in the same transverse direction, this arrangement being integrally mounted in a rectangular housing.
In this light-source unit, by arranging the small light-source modules linearly, a linear design is achieved in which it is possible to produce surface light emission with a large surface area and high light intensity, making the arrangement suitable for such applications as a brake light of a vehicle.
A ninth aspect of the present invention is a light-source unit having a plurality of light-source modules having disposed therein a small single-point light source according to any one of the first to the fifth aspects arranged in a linear pattern, wherein the narrowed ends and the opposite broadened ends of the module bodies thereof alternate in orientation along the linear arrangement, this arrangement being integrally mounted in a rectangular housing.
In this light-source unit, similar to the eight aspect, by arranging the small light-source modules linearly a linear design is achieved in which it is possible to produce a surface light emission condition. Additionally in this aspect, by alternating the orientation of the narrowed and broadened ends of the modules, it is possible to achieve a dense layout of the modules, thereby making this arrangement suitable for use as a high-mounted brake light in a vehicle.